I have seen the news as well; they did what they feel is better to secure their wallet. Although I believe even quantum computing systems will become a threat for Bitcoin, it will take a couple of decades. Still too far to compute Bitcoin private keys in reverse. However, we have to keep in mind always anything could happen with your wallet. So we have to do best practice to secure our funds. Out of quantum, we may encounter hacks or virus attacks as well. So splitting funds into different wallets increases the security.

However, whether it's a lesson or not, this is a good practice. We might take it seriously since quantum computers are becoming a threat for Bitcoin. My personal opinion is it's too early to think about quantum threats, but I agree to protect your funds in a different wallet if the amount is quite big.